Induction-motor.



E. R. KNIGHT. INDUCTION MOTOR. APPLIUATION FILED APR. 30, 1909.

Patented June 20, 1911'.

' To all whom it may concern:

UNITED STAWENT rrion EABLE RL KNIGHT, OF NORWOOD, OHIO, ASSIGNOB TO ALLIS-CHALMEBS COMFANY, A.

CORPORATION OF NEW JERSEY.

' INDUCTION-MOTOR. 7

Be it known that I, EARLE R. KNIGHT, a citizen of the United States, residing at Norwood, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvementsin Induction-Motors, of

which the following is a full, clear, and exact specification.

This invention relates to induction motors, and particularly-to the means forsecuring together the conductor, bars and short-circuiting rings of squirrel cage rotors.

In another aspect the invention relates to the method which is carried out in forming the connections.

One of the objects ofthe invention is to provide means and a method for securing together the bars and the rings of a squirrel cage rotor so as to form joints or connections which are extremely effective mechanically andelectrically, and which are very simple in construction.

A further object is to provide connecting means embodying certain members which act as fan blades to create a sufii'cient circulation-of air when the machine is in opera- 7 tion to'eflectively'cool the stator.

connection has section of the sametaken substantially along In the accompanying sheet of drawings,

Figure l is a partial sectional view of one end of a squirrel cage rotor having the bars and the rings secured together in accordance with my invention. Fig. 2 is a'partial end 1 view of the rotor, the. shaft being shown in section; Fig. 3 is a view of one end of one of the bars; Fig.4 is a similar view with the bar turned Fig. 5 is a side view of one of the keys or wedges which are utilized in securing the bars and rings together; Fig. 5* is a frontview of the key illustrated in Fig. 5; Fig. '6 is adetailed sectional elevation with parts broken away and showing a portion of one of the bars, a wedge or key, and one of the rings, this view showing the parts before the end of the bar is-upset or enlarged; Fig. 7 is a similar View looking toward the end of the machine; Fig. 8 is a top planview of the same after the joint or been completed; Fig. 9 is a the line 9- 9 of Fig. 8; and-Fig. 10 is a section of the same taken substantially 'along direction indicated by the arrow;

the line 10-10 of Fig. 9, looking in the I Specification of Letters Patent.

Referring now to the figures of the drawi ing, 10 represents the laminated core of a squirrel cage rotor, of an induction motor,

I Patented June 20, 1911. ,1 Application filed April 30, 1909. Serial No. 493,134.

said core being mounted upon a shaft 11 and the laminae being clamped between the usual end-heads, one of which is shown at 12. The

core is provided at or near the periphery with slots in which are located conductor bars 13, which project outwardly a suitable distance beyond the clamping plates 12, the bars being in this instance circular in cross section. As is shown, clearly in'the draw.-

ings and particularly ,in Figs '3 and lathe bars are provided with open slots 13 Whichf extend inwardly from the ends, forming in the end of each conductor, a forkor two j arms or end portions 13 and 13?.

At 14 is shown a short-circuit in g ring which, in this case, is spaced a short distance I from the end plate 12, andthis' ring is pro vided with openings or partially closed slots which are in alinement with the slots of the core and receive the ends of the bars. 13."

While I have shown only one endfofithe rotor, it will be understood that the construe- 1" tion at both ends of, the rotor is the same.' The slotted ends of the bars are spread or forced tightly against the walls of the slots of the rings by keys or wedges 15, each of which as is shown clearly in Figs. 5 and 5 is L-shaped, being provided with two arms 15? i and 15 which are arranged at substantially right angles to each other. The arm 15 of each key is in this case shorter than the arm 15 and has at its free end an open notch 15,

the purpose of which'will be explained, and

each key is tapered toward the'free end of" the longer arm 15 as is shown clearly in Fig.

5. hen the keys or wedges arejinserted,. they are driven tightly into the slots 13 of the bars, forcing the ends of the latter firmly into engagement with the "rings, and when the keys are driven in place, the outerportions are substantially flush with the-outer peripheries of the rings and c0re,.it being understood that the opening at the outer portion of each slot of the ring is ofsufiicient width to receive the corresponding'key or wedge and to permit it to be'driveninto place. When the keys or wedges are in place they occupy the positions shown in the drawings, that is, the longer. arms15 are located between the rings and the end plates bars are upset in a manner to be described outwardly projecting ends of The ends of-the conductors are presently the latter project beyond the rings and ends ofthekeys.

To hold the bars and keys in place, the the bars or the slotted portions which project beyond the outer surfaces of the rings are upset with a suitable tool, forming enlarged circular heads 13 and part of the metal, shown at 13 is forced'into the notches 15 of the keys.

this manner preferably by spinning operations, a spinning tool of the proper shape being employed. When the ends of the bars are spun, the metal of the two parts of each bar is united, bridging the slot between the parts and formingv a continuous circular head quite similar to that formed by an ordinary upsetting tool such as a riveter, with the exception that in spinning tliie 'netal into the notch a tapered depression 135 is formed in the head. I I

Itwill be seen that the construction which I have described above and that excellent electrical an d me'c anical connections are obtained for the reas n 'that the keys drive the'ends of the bars very tightly against the walls of the slots in the rings, thereby providing contact surfaces of considerable area, and for the reason that by .upsetting the ends of the bars and spreading the; metal into the notches of the keys, accidental displacement or even loosening of the parts is absolutely prevented. Furthermore, the inwardly projecting ends of the keys or wedges serve as fan blades to force an ample volume of air outward to cool the stator and parts of the rotor.

I do not desire to be confined to the exact details shown, but aim in my claims to cover all modifications which do not involve a departure from the spirit'and scope of my invention.

What I claim as new and desire to secure by Letters Patent is:

1. In a rotor of an induction motor, a core, conductors carried by the core-and provided with slotted ends, a short-circuitingl ring having openings receiving the ends of the conductors, and spreading members inserted in the slotted ends of the conductors, said conductors and spreading members having interlocking portions which prevent relative displacement of said parts, the locking porv tions ofsaid conductors c0 prising upset ends thereof. I I

2. In a rotor of an induction motor, a core, conductor bars carried by the core and provided with slotted ends, a short-circuiting shaped in is extrefinely simple,

. of said members.

3. In a rotor of an induction motor, a core, conductor bars carried by the core and provided with slotted ends, a short-circuiting ring having openings receiving the ends of the bars, and tapered lteys'inserted radially in the slotted portions of the conductors. said keys having notches into which the metal of the conductors is spread to prevent displacement of said members.

4. In a rotor of an induction motor, a core, conductor bars carried by the core and provided with slotted ends, a short-cirouiting ring having openings receiving the ends of the bars, and substantially L-shaped spreading members inserted in the slotted ends of the conductors, said members having axially extending portions which are notched or recessed, and portions extending radially between the rings and core, the metal of the bars being spread into the notches to prevent displacement of said members.

5. In a rotor of an induction motor, a core having conductor bars provided with slotted ends, a short-circuiting ring having openings which receive the ends of the bars, and sub stantially radially arranged spreading members inserted in the slotted ends of the bars and extending inwardly beyond the latter so as to act as fan blades.

6. In the rotor of'an induction motor, a core having conductor bars provided with slotted ends, a short-circuiting ring having openings which receive the ends of the bars, and substantially radially arranged spreading members inserted in the slotted ends of the conductors and extending inwardly beyond the latter so as to act as fan blades, said conductors shaped to prevent displacement of said members.

7. In a rotor of an induction motor, a core having conductor bars provided with slotted ends, a short-circuiting ring having openings which receive the bars, and substantially L-shaped members driven into the slots of the conductors, said members having radial portions which extend inward between the core and ring and act as fan blades, and axial portions which extend toward the ends of [20 the bars, said axial portions having notches and the ends of the bars being upset and forced into said notches.

8. In the rotor of an induction motor, a core, slotted conductors carried thereby, short-circuiting rings having openings into which said conductors extend, and fans extending through said conductors wedging together said conductors and rings.

9. In the rotor of an induction motor, a

j core, slotted conductors carried thereby, In testimony whereof I afiix my signature, shortcircuiting rings having openings into in the presence of two itnesses. v which said conductors extend, and falns havin'g spreading portions extending through 1 5' said conductors Wedging together said con- Witnesses:

ductors and rings. I 7 GEORGE EVANS,

Mi1waukee,-Wis., April 9, 1909. 'JoHN W. HOPPER.

' EARLE R. KNIGHT. 

